KABUL, Afghanistan (CNN) -- Sen. Barack Obama arrived in Afghanistan on Saturday, met with American forces and, according to a U.S. official, is expected to meet Sunday with Afghan President Hamid Karzai.

The presumptive Democratic presidential nominee was visiting the Central Asian nation before he embarks on a tour of the Middle East and Europe, a trip aimed at boosting his foreign policy credentials.

The trip, which comes four months ahead of the presidential election, marks Obama's first visit to Afghanistan.

The trip has been shrouded in secrecy for security reasons, a standard precaution for most U.S. officials in conflict zones.

The senators met service members at Jalalabad airfield in Nangarhar province.

The governor of Nangarhar province, Gul Agha Shirzai -- formerly the governor of Kandahar province -- also met the senators at the air base. Shirzai and Obama embraced briefly at the end of the meeting. Watch Obama's visit to Jalalabad »

Upon arrival at Bagram Air Base, the senators were briefed by Maj. Gen. Jeffrey J. Schloesser, commanding general of the Regional Command East.

Ahead of the trip to Afghanistan, the senators stopped in Kuwait to visit U.S. troops, Obama campaign spokesman Robert Gibbs said. They left Washington on Thursday.

Obama's Trip

Sen. Barack Obama is set to step onto the world's stage. During his trip to the Middle East and Europe, Obama will visit:

Jordan

Israel (with a trip to the West Bank-Ramallah)

Germany

France

The United Kingdom

Obama arrived in Afghanistan on Saturday and is slated to visit Iraq, although for security reasons, no public schedule for the visit has been released.

In Kuwait, the senators visited Camp Arifjan for about two hours to meet with U.S. Army Central leadership, take a brief tour of the base and talk with soldiers, U.S. military spokesman Lt. Col. Bill Nutter said.

They met in a gymnasium with about 1,000 military members, who cheered jubliantly at their arrival.

"America is unified in being so proud of the extraordinary, brilliant, dedicated professional service that is provided by all members of our armed services," he told the military personnel there.

After, Obama said, "I am just very proud of the extraordinary work that the troops are doing here in Kuwait; you're providing all the logistical support that's needed for folks in the battlefield and without you this effort would not be successful."

Hagel agreed, saying, "We're here first to thank the troops."

After the events at the the gymnasium, they met with Lt. Gen. Jim Lovelace, the U.S. Army Central Commander, and senior leadership who gave them an overview of the command, Nutter said.

Obama spoke briefly to a pool reporter about his trip just before leaving Washington.

"I'm looking forward to seeing what the situation on the ground is," Obama said. "I want to, obviously, talk to the commanders and get a sense, both in Afghanistan and in Baghdad of, you know, what the most, their biggest concerns are. And I want to thank our troops for the heroic work that they've been doing."

The fight in Afghanistan has become a more pressing issue on the political radar. Three times as many coalition soldiers and other military personnel have died this month in Afghanistan, compared with Iraq. July's death toll for coalition troops in Afghanistan reached 22 Saturday, after the Friday death of a Canadian soldier was announced.

The fight in Afghanistan has become a more pressing issue on the political radar. Three times as many coalition soldiers and other military personnel have died in July in Afghanistan than in Iraq.

On Sunday, nine U.S. soldiers were killed in a fight with about 200 Taliban militants in eastern Afghanistan. It was the deadliest attack on U.S. troops in Afghanistan in three years.

Defense Secretary Robert Gates said Wednesday that U.S. officials are looking for ways to send more troops to Afghanistan, amid the resurgence of violence nearly seven years after the ousting of the Taliban government.

Gates said the hope is to send additional forces "sooner rather than later."